Beetroot experiment

Extracts from this document...

Introduction

Nanye Osae-Asare BEETROOT REPORT PLAN The aim of the following experiment is to use beetroot to examine the effect of temperature on cell membranes and relate the effects observed membrane structure. Hypothesis I predict that upon heating beetroot to a certain temperature colour will leak out and give out a reading on a colorimeter. Scientific Background Beetroot is a vegetable which is used greatly in food making and an important ingredient in recipe books. It is usually recommended that you don't remove the outer skin of the beetroot and don't cut off all the stalk and root if you want to avoid getting lots of red dye in the cooking water. Beetroot contains red pigments called betalains, located within the cell vacuole. Normally the pigments cannot pass through membranes but they leak out when the beetroot is cooked or put in alcohol. The beetroot is protected by a cell membrane. The cell membrane functions as a semi-permeable barrier, allowing a very few molecules across it while fencing the majority of organically produced chemicals inside the cell. Electron microscopic examinations of cell membranes have led to the development of the lipid bilayer model (also referred to as the fluid-mosaic model). The most common molecule in the model is the phospholipids, which has a polar (hydrophilic) ...read more.

Middle

2 boiling tube racks 9. Crushed ice 10. 8 Boiling tubes 11. Thermometer(one per water bath) 12. Colorimeter to measure amount of colouration produced. 13. Cuvettes 14. Stop clock 15. Distilled water 16. Pipettes for measuring 2cm3 and 5cm3 17. Small measuring cylinders. Procedure 1. Cut sections from a single beetroot using a size 4 cork borer. Cut eight, 1cm length slices from these sections. Be careful not to spill beetroot juice on skin or clothing since it stains very badly. 2. Place the slices in a beaker of distilled water. Leave overnight to wash away excess dye. 3. Next day, place eight labelled boiling tubes each containing 5cm3 distilled water into water baths at 0oC, 10oC, 20oC, 30oC, 40oC, 50oC, 60oC and 70oC. Leave for 5 minutes until the water reaches the required temperature. Place one of the beetroot sections into each of the boiling tubes. Leave for 30minutes in the water baths. 4. Decant the liquid into a second boiling tube and remove beetroot sections using a technique that does not squeeze the slice e.g. spear with a pointed seeker. Shake the water/solution to disperse the dye. 5. Switch on the colorimeter and set it to read % absorbance. 6. Set the filter dial to the blue/green filter. ...read more.

Conclusion

Colorimeter reading was lowest at 0oC 4. There was a significant rise in colorimeter reading from that at 50oC and 60oC. Explanation for results 1. Colorimeter reading stood for the amounts of betalain solution that passed through the cell membrane of the beetroot. As temperature increased, so did the size of pores in the membrane which allowed more and more betalain to escape from the cell. This supports the fact that temperature and colorimeter reading was directly proportional. 2. At 70oC the pores in the beetroot's were open the widest allowing the most betalian solution to leave the vacuole through the cell membrane. This explained why the colorimeter reading was highest for the beetroot tat was heated in the 70oC water bath. 3. At 0oC, the low temperature causes the pores to constrict and less amount of betalian solution is allowed to pass through the cell membrane. Since less amount of betalain is allowed to pass through, this means that colorimeter reading will be low. The results show that this was indeed the case. 4. From 0oC to 40oC, the molecules of the betalin solution possess relatively the same amount of energy. From 50oC betalin molecules have acquired a greater amount of energy and are free to move. This combines with the effect of temperature on the cell membrane pores to allow a greater than usual amount of betalin solution to leave to cell via the cell membrane. Evaluation 1. ...read more.

Found what you're looking for?

Start learning 29% faster today

150,000+ documents available

Just £6.99 a month

or

Here's what a teacher thought of this essay

3 star(s)

Overall, this report of an investigation into the effect of temperature on the permeability of biological membranes is well-structured with a fair degree of supporting theory. Most of the key areas are covered in a logical order allowing the reader to follow the scientific process. There are, however, a number of weaknesses that would need to be addressed before submitting this as A'Level coursework. [1] The hypothesis needs to refer to the relationship between IV and DV; [2] The introduction needs to be wholly focused on the area of biology under investigation - membrane structure and effect of heat on permeability; [3] Control variables need to be discussed in full with the aim of increasing the validity of the results; [4] The results themselves need to be discussed in the light of sound biological facts with references to previous work by other biologists on the same hypothesis.

Related AS and A Level Molecules & Cells essays

A membrane is a phospholipid bilayer studded with proteins, polysaccharides and other sorts of lipids. This patchwork of molecules is like a mosaic. Because the molecules move about within their respective layer, the membrane behaves like a fluid. This is why the model is called the Fluid-mosaic model.

The double carbon bond causes a 'kink' to occur in the fatty acid, which means that the next phospholipids cannot fit as closely to it as it would have been able to if the fatty acid was saturated. This makes the cell membrane more fluid as there are gaps within the bilayer; this also makes it more permeable.

o My beetroot cylinders will be 6mm in diameter and 30 mm in length. o I have decided that with the colorimeter I will be using a blue filter because it is opposite to red in the spectrum and so the red will absorb the blue giving a measurement.

Out of 8 patients who had genetically modified tissue surgically inserted into their brain, 6 of them have shown improvements in the condition. Tests have shown that the treatment slowed cognitive decline by as much 50%. [7] Conclusion Despite being discovered almost 100 years ago, there has been little definitive progress in actually curing Alzheimer's.

Also, the support given by the xylem vessels may be unwanted since it would be exposing more of the plant towards the sun and risk even greater water loss. Yet another possible advantage of specialization would be the capability of the organism to increase in size.

other environmental factors, therefore there is a need for constant regeneration of the cells. The epidermis itself varies in thickness, but averages out at around 0.25mm in thickness. As the process of skin regeneration occurs the new skin cells pass through each of these layers in turn, this process lasts approximately one month from start to finish.

In hot habitats it is an advantage to a mammal to increase the surface area of the body to increase the rate of heat loss. Blood vessels near the surface of the skin help to regulate body temperature by: * Cooling the body from the core of the body *

There are two electrical contact layers, which allow electric current to flow in and out of the cell. The electrical contact layer at the top the top of the cell where the light enters is made of a good conductor, for example a metal.